The long-term objective of the project is to develop techniques for studying the visual capacities of infants, and to carry out substantive studies of the development of human vision. Both normal and non-normal vision are of interest. Specifically, the present proposal concerns the further development of the forced-choice preferential looking (FPL) technique, and its use in substantive studies of color vision and spatial summation. In the color vision studies, we propose to continue our investigation of color blindness and color anomalies, document the influence of the size and shape of test targets, and trace out saturation and wavelength discrimination functions on infants 1, 2, and 3 months of age. In terms of technique development, we plan to modify the FPL technique so that it can be used to test visual capacities at specified retinal eccentricities; and to test the size of Ricco areas at different retinal locations in infants.